Monomeric Boron and Tin(II) Heterocyclic Derivatives of 1,8‐Diaminonaphthalenes: Synthesis, Characterization and X‐ray Structures

The reaction of the diaminonaphthalene dilithium salt(THF) 2 Li 2 [(NSiMe 3 ) 2 C 10 H 6 ] with BX 3 (X = Cl, Br) in hexane provides the monomeric compounds BX[(NSiMe 3 ) 2 C 10 H 6 ] [ 3 (X = Cl), 4 (X = Br)] with a tricoordinate boron atom. Attempts to reduce 3 and 4 with lithium, sodium, potassium or sodium/potassium alloy with the intention to isolate a boranide resembling a carbene were unsuccessful. However, the diaminonaphthalene dilithium salt (THF) 2 Li 2 [(NSi‐ i Pr 3 ) 2 C 10 H 6 ] ( 2 ) reacts with SnCl 2 in THF to provide the carbene analog 5 . Compounds 2 , 3 and 5 were characterized by single‐crystal X‐ray structure analysis. The structures of 3 and 5 show the naphthalene backbone to be nearly planar, while the heterocycles in 3 and 5 containing boron and tin atoms, respectively, have torsion angles ( 3 : 30.06°; 5 : 37.27°) with respect to the naphthalene plane. The boron atom has a trigonal‐planar environment, and the stannylene tin–nitrogen bonds form a very acute N–Sn–N angle of 92.2°.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)